Prior art devices designed to provide linear actuation using the expansion of material as a primary actuator are considerably complicated, expensive, and lack robustness.
One such linear actuator is described in U.S. Pat. No. 5,705,863, which teaches a linear actuator having a magnetostrictive rod which is magnetically energized under analog logic control in operative relation to a pair of electrically disengaged one-way locking devices, one of which is interconnected with the actuator through a stroke multiplier to provide a high force, high speed motor drive. Two-stage operation of the stroke multiplier is effected through levers angularly displaced by angular deformation of the magnetostrictive rod about a pivotal axis offset from the rod axis by means of a flexible support for such levers to avoid wear and backlash. This structure results in a complicated, expensive device.
Accordingly, it is desirable to provide a simple, inexpensive and robust linear actuator.